Water heater



FIG. 1 is a front elevational view of a water heater showing my new design;

FIG. 2 is a side elevational view thereof;

FIG. 3 is an opposite side elevational view thereof;

FIG. 4 is a top plan view thereof

FIG. 5 is a bottom plan view thereof; and,

FIG. 6 is a rear elevational view thereof.

The broken-line disclosure in the view is understood to represent unclaimed subject matter which forms no part of the claimed design. 

The ornamental design for a water heater, as shown and described. 